Reliability of a two-colour chewing gum test to assess masticatory performance in complete denture wearers.

The aim of this study was to test the reliability of a method to measure the masticatory performance of complete denture wearers employing a colour-mixing ability test and assessment by visual and electronic colourimetric analysis. A sample of 75 subjects was selected from patients who received new conventional complete dentures. Masticatory tests were performed using a two-colour chewing gum that was masticated for 5, 10, 20, 30 and 50 chewing cycles, performed in a random order. The mixing level of the two colours of the chewed gum was assessed visually by two independent raters based on a 5-point ordinal scale. The specimens were flattened into a 1-mm-width wafer, scanned and saved as a two-sided digital image. Each pair of images was submitted to an electronic colourimetric analysis to assess the level of colour mixture, measured by the circular variance of hue (VOH). Overall inter- and intra-rater agreements in visual analysis were 64% and 68%, respectively (almost 99% of scores ranged within ±1 point), whilst overall weighted kappa was >0.80. A proportional increase in the level of mixture occurred with increased number of chewing cycles (P < .001). Similarly, VOH and the visual analysis were highly correlated (r = -.89; P < .001). Bland-Altman plots revealed excellent agreement and extremely low systematic error between duplicated VOH measures. It was concluded that the two-colour chewing gum test is a reliable method to assess the masticatory performance in complete denture wearers using both visual and electronic colourimetric analyses.

Mini-Implants for Mandibular Overdentures: Cost-Effectiveness Analysis alongside a Randomized Trial.

Mandibular overdentures retained by 2 conventional implants have been considered the standard of care for complete edentulism, according to the McGill and York consensuses. However, many patients refuse this treatment modality due to the associated costs and postsurgical discomfort. Mini-implants have the chance to overcome these limitations due to their potentially lower costs and a relatively uncomplicated surgical technique. This study compared treatment costs and incremental cost-effectiveness following the insertion of mini-implants (2 or 4) or 2 standard-size implants for the retention of mandibular overdentures, by means of a randomized clinical trial. In total, 120 edentulous participants (mean age 59.5 ± 8.5 y) were randomly allocated into 3 groups according to treatment received: 4 mini-implants (group 1), 2 mini-implants (group 2), or 2 standard implants (group 3). Treatment costs and outcomes (Oral Health Impact Profile for Edentulous [OHIP-EDENT] and satisfaction with the dentures) were evaluated after 6 mo. Incremental cost-effectiveness ratios (ICERs) were calculated for each intervention in terms of cost per 1-point change in patient outcomes. A 1-way sensitivity analysis was performed considering a 95% confidence interval variation in cost and outcome parameters, represented in tornado diagrams. Overall treatment cost was the lowest for group 2 (average cost: US$318.08), followed by group 1 (US$510.75) and group 3 (US$566.13). Groups did not differ in terms of the length of unscheduled appointments and time spent by participants. In summary, our findings indicate that mandibular overdentures retained by 2 or 4 mini-implants are less costly compared to 2-implant overdentures. Despite the lower costs of overdentures retained by 2 mini-implants, those retained by 4 mini-implants showed further improvement in patient-reported outcomes and reduced costs compared to standard implants ( ClinicalTrials.gov NCT01411683). Knowledge Transfer Statement: This report shows that mini-implant retained overdentures are less costly than overdenture treatment on 2 standard-sized implants. Treatment with 2 mini-implants is an effective procedure to substantially save resources, whereas treatment with 4 mini-implants provides better results from a patient perspective combined with slightly reduced costs compared to the treatment with 2 standard implants. Therefore, mini-implant overdentures may be effective and more accessible than overdentures on 2 standard-size implants for those with limited incomes.

Mandibular complete denture versus single-implant overdenture: a systematic review of patient-reported outcomes.

The single-implant mandibular overdenture (SIMO) has been proposed as an alternative for edentulous patients who are poorly adapted to their dentures due to low retention and stability of the conventional mandibular complete denture (CD). However, there is a lack of evidence regarding the effectiveness of SIMO, which can be measured by examining patient perception of treatment effects. The aim of this systematic review was to assess the comparative results of CD and SIMO treatments using patient-reported outcome measures. A literature search was carried out in PubMed, Scopus and Cochrane Central databases. The search included studies published up to July 2017. The focus question was: 'Do single-implant mandibular overdentures improve patient-reported outcomes compared to conventional complete dentures in edentulous patients?' Eligible studies were randomised clinical trials (RCT) and prospective studies. After initial screening for eligibility and full-text analysis, 11 studies were included for data extraction and quality assessment (five parallel-group RCTs, two crossover RCTs and four prospective studies). All studies reported marked improvement in satisfaction with the dentures and quality of life measures after SIMO treatment, irrespective of variations in implant treatment protocols and retention systems. Methodological considerations revealed a lack of evidence from RCTs on the comparative effectiveness of the two treatment strategies. Hence, although available evidence suggests considerable improvement in patient-reported outcomes following the insertion of a single implant to retain a mandibular denture, further well-designed comparative studies between SIMO and CD are required to improve the level of evidence and to support the indication of SIMO treatment in routine practice.

Identifying student profiles and their impact on academic performance in a Brazilian undergraduate student sample.

The recognition of the student profile provides strategic information for planning educational policies in the university environment. The aims of this study were to identify natural segmentation of freshman undergraduate dental students based on demographic, socioeconomic and educational variables, and to subsequently investigate their impact on academic performance of Brazilian undergraduate students. Cluster analysis (two-step algorithm) was used to segment students who entered dental school in the time period from 1999 to 2001 (n=158) into groups based on responses to a questionnaire completed by students at the time of the admission examination. Clustering analysis revealed three natural groups. Age, the parents' level of education, and performance on the first admission test were the most important variables for cluster segmentation. Cluster 1 (n=42; 26.6%) was characterized by female students with higher socioeconomic status and better previous educational indicators. Cluster 2 (n=62; 39.2%) represented disadvantaged socioeconomic profiles, with a predominance of females and older students. Cluster 3 (n=54; 34.2%) showed similar socioeconomic characteristics to cluster 1, except for male prevalence, higher age, and experiencing difficulty in the admission test. Clusters' academic performance was satisfactory in both overall course and course groups (grade point average of at least 7.0), with average ranging from 7.89 (SD=0.44) to 8.13 (SD=0.31) and 7.37 (SD=0.75) to 8.31(SD=0.26), respectively. Our findings provide encouraging evidence for the current context of equality of access to education and reveal the importance of financial support to maximize successful educational experiences of socioeconomically disadvantaged dental students.

Digital subtraction radiography evaluation of longitudinal bone density changes around immediate loading implants: a pilot study.

OBJECTIVE: The aim of this study was to assess longitudinal quantitative changes in bone density around different implant loading protocols and implant surfaces measured by digital subtraction radiography (DSR). METHODS: 12 patients received bilateral homologous standard and TiUnite® (Nobel Biocare, Kloten, Switzerland) single-tooth implants under 2 implant-loading protocols: immediate loading (8 patients, 16 implants, 12 maxillary) and conventional loading (4 patients, 8 implants, 4 maxillary). Standardized periapical radiographs were taken immediately after implant placement (baseline image) and at the 3-month, 6-month and 12-month follow ups. Radiographic images were digitized and submitted to digital subtraction using the DSR system® (Electro Medical System, Nyon, Switzerland), resulting in three subtracted images. Quantitative analysis of bone density was performed using Image Tool® software (University of Texas Health Science Centre, San Antonio, TX) to assess pixel value changes in five areas around the implants (crestal, subcrestal, medial third, apical-lateral and apical). RESULTS: Repeated-measures analysis of variance showed that grey levels were significantly influenced by follow-up time and implant-loading protocol. A linear increase in grey levels was found for immediate loading (IML) implants and a significant decrease in grey levels was observed in the 12-month follow up for conventional loading implants. No effect of implant surface treatment was observed. CONCLUSION: In conclusion, IML protocol induced mineral bone gain around single-tooth implants after the first year under function for cases with favourable bone conditions.

Factors influencing edentulous patients' preferences for prosthodontic treatment.

The aim of this study was to identify factors influencing edentulous patients' preferences for treatment using conventional or implant dentures (ID). A consecutive sample of 112 patients was selected in a university facility. All patients responded to a questionnaire concerning preferences about treatment and factors influencing preferences for conventional complete dentures (CD), implant-retained overdentures (IRO) and fixed implant-supported prostheses (FISP). Subsequently, a set of 21 questions was presented, and patients were requested to rate the importance of various potential reasons influencing their choice of treatment. Preference for CD was more prevalent for maxilla (52·7%) and mandible (41·1%). Fixed implant-supported prostheses and IRO were preferred for the mandible (FISP=37·5%; IRO=21·4%) rather than maxilla (FISP=27·7%; IRO=19·6%). The most preferred treatment option among the subjects when evaluating both arches was the implant-supported fixed or removable prosthesis (FISP/IRO). A preference for combined upper and lower CD was also commonly reported (39·3%). Factor analysis identified six components that accounted for 72·2% of the total variance: (i) psychosocial benefits, (ii) functional performance, (iii) technical and financial concerns, (iv) post-insertion complaints, (v) removability and (vi) longevity. Technical and financial concerns (cost, complexity, surgery risks and duration of treatment) were more relevant for those who preferred ID (P<0·001). With the exception of post-insertion complaints, all mean scores of component factor loadings were positive for ID. Conventional complete dentures are associated with lower expected outcomes by patients, and cost-related issues are the major factors associated with the preferences for implant treatment of edentulous patients.

Do computed tomography and magnetic resonance imaging add to temporomandibular joint disorder treatment? A systematic review of diagnostic efficacy.

A question frequently asked in the clinical practice of the professional who treats temporomandibular joint disorders (TMJD) is 'To make the cost/benefit ratio worthwhile for the patient, when should I request a temporomandibular joint (TMJ) computed tomography (CT) or magnetic resonance imaging (MRI)?' To evaluate the evidence of the efficacy of CT and MRI in the diagnosis of disc displacement, local inflammatory disorders, and arthrosis of the TMJ at therapeutic efficacy level, PubMed and Cochrane literature searches with specific indexing terms and a hand search were made. From the retrieved titles and abstracts, three examiners selected publications on the basis of predetermined inclusion and exclusion criteria. Data were extracted from the selected publications using a previously established protocol. Publications considered relevant were interpreted with the aid of the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool and publications that critically evaluate systematic reviews. The literature search yielded 584 titles and abstracts, of which 257 were selected and read in full text. One study was judged relevant. This study evaluated evidence of the efficacy of MRI in the diagnosis of disc position and configuration, disc perforation, joint effusion, and osseous and bone marrow changes in the temporomandibular joint, but no publication reported diagnostic thinking efficacy or therapeutic efficacy. In conclusion, the absence of studies on the therapeutic efficacy of MRI and CT on TMJD reinforces the need for investment in decision-making studies; meanwhile, sectional imaging tests should be prescribed with caution, especially when health budgets are limited.

Digital subtraction radiography evaluation of the bone repair process of chronic apical periodontitis after root canal treatment.

AIM: To monitor radiographically the progress of bone repair within chronic periapical lesions after root canal treatment using digital subtraction radiography (DSR). METHODOLOGY: Twelve patients with 17 single-rooted teeth with chronic apical periodontitis associated with an infected necrotic pulp were selected for root canal treatment. Periapical radiographs were taken before treatment (baseline) and immediately post-treatment, 45, 90, 135 and 180 days after treatment. The radiographic protocol included the use of individualized film holders with silicone bite blocks. The six radiographic images were digitized and submitted to digital subtraction using DSR software, resulting in five subtracted images (SI). Quantitative analysis of these SI was performed using Image Tool software to assess pixel value changes, considering a step-wedge as the gold standard and a cut-off value of 128 pixels. The aim was to identify any increase or decrease in mineral density in the region of the periapical lesion. RESULTS: A minor decrease in mineral density at the canal filling session and a significant progressive mineral gain in the following evaluations (P < 0.001) occurred. Pairwise comparison of pixel grey values revealed that only the 180-day follow-up differed significantly from the previous SI. CONCLUSION: Digital subtraction radiography is a useful method for evaluating the progress of bone repair after root canal treatment. Noticeable mineral gain was observed approximately 90 days after root canal filling and definite bone repair after 180 days.

An exploratory survey of diagnostic methods for bone quality assessment used by Brazilian dental implant specialists.

Bone quality (BQ) has been described as an important predictor for the outcome of dental implant treatment. It is, however, unclear how this factor is assessed in the dental practice routine. The aim of this study was to investigate what Brazilian dental implant specialists know and understand about BQ, if they include BQ assessments in their treatment planning and which methods they use to assess BQ. A questionnaire was posted to Brazilian dental implant specialists, containing open and closed questions about their knowledge and understanding of BQ assessment, and 221 answered the questionnaire. Data were gathered and methods for BQ assessment were grouped using hierarchical cluster analysis. Answers about BQ knowledge and understanding were categorized into quantity of cortical and marrow bone (n = 72), density (n = 55), type of bone (n = 35), bone height (n = 30), bone thickness (n = 27), primary stability (n = 24) and other less common categories. BQ assessment was judged relevant to be considered a selection criterion for implant treatment. Overall frequency analysis showed that methods were roughly divided into usual (n > 170) and unusual methods (n < 9). Cluster analysis grouped BQ assessment methods into four clusters: unusual methods (DEXA, resonance frequency, Periotest and occlusal radiography), perioperative methods (peak insertion torque and tactile perception), sectional imaging (computed tomography) and plain films (periapical and panoramic radiographs). No consensus on BQ understanding or the clinical application of methods to assess BQ was found in this survey. The selection of methods shows a clear natural grouping from basic to advanced strategies for BQ assessment by Brazilian specialists in dental implants.

Exploratory factor analysis of the Brazilian OHIP for edentulous subjects.

The use of seven domains for the Oral Health Impact Profile (OHIP)-EDENT was not supported for its Brazilian version, making data interpretation in clinical settings difficult. Thus, the aim of this study was to assess patients' responses for the translated OHIP-EDENT in a group of edentulous subjects and to develop factor scales for application in future studies. Data from 103 conventional and implant-retained complete denture wearers (36 men, mean age of 69.1 +/- 10.3 years) were assessed using the Brazilian version of the OHIP-EDENT. Oral health-related quality of life domains were identified by factor analysis using principal component analysis as the extraction method, followed by varimax rotation. Factor analysis identified four factors that accounted for 63% of the 19 items total variance, named masticatory discomfort and disability (four items), psychological discomfort and disability (five items), social disability (five items) and oral pain and discomfort (five items). Four factors/domains of the Brazilian OHIP-EDENT version represent patient-important aspects of oral health-related quality of life.

Differential infiltration of CD8+ and NK cells in lip and oral cavity squamous cell carcinoma.

BACKGROUND: CD8+ and natural killer (NK) cells have been considered the most effective cells in the combat of cancer, contributing to better prognosis and longer survival. METHODS: The aim of this study was to evaluate the population of CD8+ and NK cells, by immunohistochemistry, in samples of oral cavity squamous cell carcinoma (OCSCC) and lip squamous cell carcinoma (LSCC), leukoplakia, actinic cheilitis, and healthy oral mucosa (control). The relationship of CD8+ and NK cells with survival data, lymph node metastasis, tumor size, and proliferative index was also evaluated. RESULTS: The number of peritumoral and intratumoral CD8+ and NK cells was significantly higher in LSCC, when compared with control, pre-malignant lesions, and OCSCC. A higher proportion of peritumoral CD8+ cells demonstrated correlation with a lower neoplastic proliferative index. Moreover, patients with OCSCC with a high density of peritumoral CD8+ cells showed a tendency towards a longer survival time. CONCLUSIONS: The differential CD8+ and NK cells infiltration in oral SCC might reflect a distinctive tumor microenvironment with a favorable local cytotoxic immune response against neoplastic cells.

Discriminant analysis of patients' reasons for choosing or refusing treatments for partial edentulism.

The aim of the study was to explore partially edentulous patients' reasons for choosing or refusing prosthodontic treatment with removable partial dentures (RPD), fixed partial dentures (FPD) and implant partial dentures (IPD). Clinical and oral health-related quality of life measures were collected from 165 partially edentulous patients undergoing treatment. Patients' preferences were recorded and reasons for choosing or refusing treatments were measured with 32 questions using a five-point Likert scale. Descriptive statistics, chi-square and multiple logistic regression were used to compare patients' preferences according to clinical variables. Discriminant analysis was used to examine the impact of each reason for a patient's decision to choose or refuse treatment options. Results showed that older patients (P < 0.001) and with greater oral-related quality of life impacts (P < 0.05) were more likely to choose RPD. IPD were preferred by patients with higher education levels (P < 0.01). Discriminant functions revealed that the desire to have a fixed or removable denture had great impact on preferences. Removal of tooth structure was the main reason for refusing FPD and financial cost had a great impact on refusing IPD. Overall agreement between observed patients' decisions and those predicted by the discriminant function was >90% for all treatments. Reasons vary greatly among patients, and the role of individual perception of potential reasons for treatment selection was the most important determinants of patients' decisions. The main reasons for choosing or refusing treatments focused in this study can be used to guide shared decision-making, providing treatments that better match patients' expectations and desires.

In vivo study of pixel grey-measurement in digital subtraction radiography for monitoring caries remineralization.

OBJECTIVES: The aim of this study was to evaluate the performance of a quantitative method, based on pixel grey value measurements, for monitoring caries remineralization. METHODS: Proximal radiographs of 11 patients (61 enamel caries lesions) were taken both before and after a 2 month remineralization protocol. Radiographs were digitized and for each area a follow-up image was subtracted from a baseline image. A quantitative analysis was undertaken using ImageTool software (University of Texas Health Science Center, San Antonio, TX). For each caries lesion diagnosed, a mean pixel value was obtained in digital subtraction radiographs (SR) using a scale ranging from 0-255 grey values. To identify caries status after the remineralization protocol, a subjective analysis of SR was undertaken by 6 radiologists who graded the lesions as demineralized (n = 10), unchanged (n = 34) or remineralized (n = 17). RESULTS: There was a statistically significant difference between the mean pixel values for demineralized (112.1+/-14.4), unchanged (127.3+/-12.3) and remineralized (137.5+/-13.8) lesions. CONCLUSIONS: It was concluded that the status of proximal caries lesions after remineralization therapy can be assessed by pixel grey measurements in SR and may constitute a suitable complementary method for monitoring the results of remineralization protocol in clinical practice.

Assessing perceived potential outcomes of prosthodontic treatment in partial and fully edentulous patients.

The aim was to develop an instrument to measure and to explore the perception of potential outcomes of prosthodontic treatment in partial and fully edentulous patients, including benefits, risks and consequences of non replacement of missing teeth. It was also aimed to assess the influence of clinical and socio-demographic variables on the perception of potential outcomes. Using a two-phase data collection (open-ended and closed-form), a scale was developed containing 41 statements to measure subject's perception scores in a 5-point Likert-type scale (1, strongly disagree; 2, disagree; 3, neutral; 4, agree; 5, strongly agree). In the second phase 126 partially or fully edentulous subjects were interviewed. Influence of age, gender and clinical variables on perceived outcomes were tested using one-way anova, independent t-test and two-way anova (general linear model). Respondents' mean age was 51.8 years (s.d.=12.3), and 74% were female. Cronbach's alpha coefficient of the scale and subscales ranged from 0.70 to 0.90. Patients' mean scores ranged from 2.37 to 4.88 (mean=4.25; s.d.=0.65), indicating that subjects tended to agree with the proposed affirmatives (scores 4 and 5). Perception scores were influenced by age, gender, edentulous spaces and use of prosthodontics. Older subjects, female, those with higher number of missing teeth and who have been previously treated had greater perception of benefits and risks of prosthodontic treatment. It was concluded that the proposed instrument was suitable for measuring subjects' perception of potential outcomes of prosthodontic treatment.

Quality of life of public health service dental hygienists in Goiânia, Brazil.

The aim of this study was to assess quality of life (QoL) and related factors among dental hygienists. A cross-sectional study was conducted in a sample of dental hygienists working in the public health service of Goiânia, Central-West Region, Brazil, in 2004. All active dental hygienists received a mailed questionnaire containing the shortened version of the World Health Organization instrument to measure quality of life (WHOQOL-Bref), demographic and job-related data, and questions about self-rated general health status and QoL. Response rate was 58.5% (n = 93). Descriptive statistics, simple and multiple logistic regressions were used in the analysis of data. The WHOQOL-Bref instrument revealed that the Social Relationships domain had the highest mean score (70.56), followed by the Physical (65.49), Psychological (61.3) and Environment domains (56.25). Most of the dental hygienists had a high QoL in the Social Relationships domain and a low QoL in the Physical, Psychological and Environment domains. There was an association between self-rated health status and the Physical domain; satisfaction with health and the Physical, Psychological and Social Relationships domain and self-rated QoL and the Psychological and Social Relationships domains. The conclusion is that a low QoL was common among the dental hygienists and has perceptible effects on their perceptions of their health status and QoL.

Bonding strength between a hard chairside reline resin and a denture base material as influenced by surface treatment.

Direct relining of dentures made with hard chairside reline resins is faster than laboratory-processed reline systems and the patient is not without the prosthesis for the time necessary to perform the laboratory procedures. However, a weak bond between the autopolymerizing acrylic reline resins and the denture base material has been observed. This study evaluated the effect of six different surface treatments on the bond strength between a hard chairside reline acrylic resin and a heat-cured acrylic resin. Specimens of the heat-cured acrylic resin were divided into seven groups. One of these groups remained intact. In the other groups, a 10-mm square section was removed from the centre of each specimen. The bonding surfaces were then treated with (i) methyl methacrylate monomer, (ii) isobutyl methacrylate monomer, (iii) chloroform, (iv) acetone, (v) experimental adhesive and (vi) no surface treatment -- control group. Kooliner acrylic resin was packed into the square sections and polymerized. The bonding strength was evaluated by a three-point loading test. The results were submitted to one-way analysis of variance (ANOVA) followed by a Tukey multiple range test at a 5% level of significance. No significant difference was found between the surface treatment with Lucitone 550 monomer or chloroform, but both were stronger than the majority of the other groups. The bond strength provided by all the surface treatments was lower than that of the intact heat-cured resin.